Reading comprehension is considered one of the most important skills in our society, yet there has been a paucity of research in developing construct valid instruments to measure it. The objective of the proposed study is to develop a state-of-the-art construct measurement system for reading comprehension. The capability to develop such a measurement system is made possible through the item engineering methodology developed by Stenner, Smith, and Burdick (1983). The central theme of the methodology is simple, yet elegant: until we understand what characteristics or features of test items are responsible for making items difficult or easy, we do not really know what we are measuring. Once the features of test items responsible for their difficulty have been specified, it becomes possible to truly "engineer" test items. Employing this methodology to the measurement of reading comprehension, the following tasks will be achieved: 1. Development of a microcomputer based model for assessing written discourse. 2. Development of 300 minipassage items that will span the reading scale from second grade level through graduate school. 3. Design plan for creating a rich criterion and normative frame of reference for the scale.